Development of an ultrafast laser system based on a Yb-doped fiber and a Yb:YAG thin-rod for the preclinical study of pigmented lesions treatment using a Hartley guinea pig.

In this research, we developed an ultrafast laser system based on a Yb-doped fiber oscillator and Yb:YAG thin-rod amplifier to investigate the efficacy of the laser for the treatment of pigmented lesions. The developed laser exhibited an output power of 22.7 W, center wavelength of 1030 nm, repetition rate of 495 kHz, pulse energy of 45.

Flexible-type ultrathin holographic endoscope for microscopic imaging of unstained biological tissues.

Ultrathin lensless fibre endoscopes offer minimally invasive investigation, but they mostly operate as a rigid type due to the need for prior calibration of a fibre probe. Furthermore, most implementations work in fluorescence mode rather than label-free imaging mode, making them unsuitable for general medical diagnosis. Herein, we report a fully flexible ultrathin fibre endoscope taking 3D holographic images of unstained tissues with 0.

8 W 240 fs diode-pumped Yb:YO ceramic thin-rod femtosecond amplifier.

A diode-pumped Yb:YO ceramic thin-rod amplifier which operates in the femtosecond regime is studied here. In a single-stage and direct four-pass amplification scheme, the amplifier delivers maximum output power of 8.1 W at a center wavelength of 1030.

Label-free neuroimaging in vivo using synchronous angular scanning microscopy with single-scattering accumulation algorithm.

Label-free in vivo imaging is crucial for elucidating the underlying mechanisms of many important biological systems in their most native states. However, the applicability of existing modalities has been limited to either superficial layers or early developmental stages due to tissue turbidity. Here, we report a synchronous angular scanning microscope for the rapid interferometric recording of the time-gated reflection matrix, which is a unique matrix characterizing full light-specimen interaction.

Comparative study of Yb:KYW planar waveguide lasers Q-switched by direct- and evanescent-field interaction with carbon nanotubes.

Both direct- and evanescent-field interactions with carbon nanotubes (CNTs) are applied to achieve stable Q-switched operation of Yb:KYW planar waveguide lasers. The performance characteristics were investigated in a same cavity configuration and analyzed in detail in the following three cases, CNTs deposited onto end mirror (M-coating), output coupler (OC-coating) and top surface of the planar waveguide (WG-coating). Maximum output powers, repetition rates, and minimum pulse durations are 61 mW, 1103 kHz and 215 ns for OC-coating, 39 mW, 1052 kHz and 275 ns for WG-coating, and 26 mW, 1119 kHz and 217 ns for M-coating, respectively.

Exploring anti-reflection modes in disordered media.

Sensing and manipulating targets hidden under scattering media are universal problems that take place in applications ranging from deep-tissue optical imaging to laser surgery. A major issue in these applications is the shallow light penetration caused by multiple scattering that reflects most of incident light. Although advances have been made to eliminate image distortion by a scattering medium, dealing with the light reflection has remained unchallenged.

Study of operation dynamics for crystal temperature measurement in a diode end-pumped monolithic Yb:YAG laser.

A temperature measurement scheme was proposed in a diode end-pumped thin monolithic Yb:YAG laser by analyzing the red-shifting behaviors of each lasing peak. The amount of peak shift was measured on the basis of the threshold lasing spectrum by using a chopped pump beam. In order to determine the effective scale factor, the ratio between the peak shift and the temperature rise, the dynamics of the spectral shift, the output beam profile, and the output power were investigated.

Gigahertz repetition rate, sub-femtosecond timing jitter optical pulse train directly generated from a mode-locked Yb:KYW laser.

We show that a 1.13 GHz repetition rate optical pulse train with 0.70 fs high-frequency timing jitter (integration bandwidth of 17.

Relation between transmission eigenchannels and single-channel optimizing modes in a disordered medium.

The wave transport through disordered media, although a random process, has some universal physical properties. One of these properties that has been investigated in this report is the relation between transmission eigenchannels and the so-called single-channel optimizing mode, which maximizes the intensity of the transmitted wave at a single specific output channel. Since single-channel optimizing modes have higher transmittance than the uncontrolled waves, it has been predicted before that transmission eigenchannels with higher transmittance preferentially contribute to the single-channel optimizing modes in proportion to the square of eigenvalues.

1.2-GHz repetition rate, diode-pumped femtosecond Yb:KYW laser mode-locked by a carbon nanotube saturable absorber mirror.

We demonstrate a 1.2-GHz repetition rate, diode-pumped, self-starting, 168-fs (FWHM) pulsewidth Yb:KYW laser mode-locked by a carbon nanotube (CNT) saturable absorber mirror. To our knowledge, this result corresponds to the highest repetition rate from CNT-mode-locked femtosecond bulk solid-state lasers, reaching the GHz regime for the first time.

Lag synchronization in coupled Nd:YAG lasers pumped by laser diodes.

We experimentally investigate lag synchronization in mutually coupled Nd:YAG lasers. Two laser diode pumped Nd:YAG lasers, when they are electronically coupled, exhibit lag synchronization for a strong coupling strength region. We investigate the synchronous behaviors of the lasers by analyzing error dynamics, phase portraits, and similarity function.